这里有个英文R 编程问题。

Use for loop and y <- rnorm(100) to generate a random sample of 100 numbers from a normal distribution. Calculate the mean and standard deviation of y. Now put the calculation in a loop and repeat 25 times. Store the 25 means in a vector named av. To do that, you need to define a vector of NAs of length 25, using the R command av <- rep(NA, 25), before the for loop Calculate the standard deviation of the values in av.

楼主只是懂一点点R 所以codes里有问题，无法产生题目中要求的结果。

av <- rep(NA, 25)
for (i in 1:25)
{ y <- rnorm(100)
  av <- mean(y)}
sd(av)

期待高手帮忙解答。